Volume 638, June 2020
|Number of page(s)||8|
|Section||Stellar structure and evolution|
|Published online||09 June 2020|
Neutron star matter equation of state including d*-hexaquark degrees of freedom
Department of Physics, University of York, Heslington, York Y010 5DD, UK
2 Department of Physics, Imperial College London, London SW7 2AZ, UK
3 INFN Sezione di Catania, Dipartimento di Fisica “Ettore Majorana”, Università di Catania, Via Santa Sofia 64, 95123 Catania, Italy
Accepted: 12 April 2020
We present the extension of a previous study where, assuming a simple free bosonic gas supplemented with a relativistic mean-field model to describe the pure nucleonic part of the equation of state, we studied the consequences that the first non-trivial hexaquark d*(2380) could have on the properties of neutron stars. Compared to that exploratory work, we employ a standard non-linear Walecka model including additional terms that describe the interaction of the d*(2380) di-baryon with the other particles of the system through the exchange of σ- and ω-meson fields. Our results show that the presence of the d*(2380) leads to maximum masses compatible with recent observations of ∼2 M⊙ millisecond pulsars if the interaction of the d*(2380) is slightly repulsive or the d*(2380) does not interact at all. An attractive interaction makes the equation of state too soft to be able to support a 2 M⊙ neutron star whereas an extremely repulsive one induces the collapse of the neutron star into a black hole as soon as the d*(2380) appears.
Key words: equation of state / dense matter / stars: neutron
© ESO 2020
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